Hide open doc button when not inspecting anything

(cherry picked from commit 80e4c8626d1ff648cf8ed1263cb24954f9fc1ccf)

editor/inspector_dock.cpp

@@ -414,6 +414,7 @@ void InspectorDock::update(Object *p_object) {
 	current = p_object;
 
 	if (!p_object) {
+		open_docs_button->set_disabled(true);
 		object_menu->set_disabled(true);
 		warning->hide();
 		search->set_editable(false);
@@ -429,7 +430,7 @@ void InspectorDock::update(Object *p_object) {
 	editor_path->enable_path();
 
 	resource_save_button->set_disabled(!is_resource);
-	open_docs_button->set_visible(is_resource || is_node);
+	open_docs_button->set_disabled(!is_resource && !is_node);
 
 	PopupMenu *resource_extra_popup = resource_extra_button->get_popup();
 	resource_extra_popup->set_item_disabled(resource_extra_popup->get_item_index(RESOURCE_COPY), !is_resource);
@@ -570,7 +571,7 @@ InspectorDock::InspectorDock(EditorNode *p_editor, EditorData &p_editor_data) {
 
 	open_docs_button = memnew(Button);
 	open_docs_button->set_flat(true);
-	open_docs_button->set_visible(false);
+	open_docs_button->set_disabled(true);
 	open_docs_button->set_tooltip(TTR("Open documentation for this object."));
 	open_docs_button->set_icon(get_icon("HelpSearch", "EditorIcons"));
 	open_docs_button->set_shortcut(ED_SHORTCUT("property_editor/open_help", TTR("Open Documentation")));